1. Field of the Invention
The invention relates generally to high data rate communication systems and more specifically to a high data rate communication network employing an adaptive sectored antenna.
2. Description of the Related Art
Conventionally, sectored antennas are employed in military applications. For example, a base unit transmits a message for a mobile unit or units that are deployed on a battlefield. An enemy employs a jamming device to prevent a mobile unit from receiving the intended signal sent by the base unit. A mobile unit that employs an adaptive sectored antenna can discriminate between the jamming signal and hone in on the intended message sent by the base unit. In other words, the mobile unit can steer the adaptive sectored antenna so that the antenna spatially ignores the jamming signal and focuses or hones in on the intended signal.
With the proliferation of electronic devices that communicate with other devices at a high data rate, there is an increasing demand for wireless communications in the home or workplace. For example, a user of a portable laptop computer does not want to be tethered to a particular desk or work area and, instead, demands the flexibility of portable devices (e.g., a laptop, PDA, etc.). Moreover, there is a consumer demand for the reduction in the number of physical wires and connections that are needed between the electronic devices found in one's home. For example, it would be desirable for a consumer to have a single access point for multimedia data (e.g., a cable television connection) and a wireless connection between that connection of multimedia data and consumer appliances that play or record such data. It is cumbersome for each television or VCR to have a separate connection, and it would be desirable instead to have a wireless link between the multimedia data port and the appliances.
A significant hurdle in implementing a high data rate communications system in a home environment is the interference from adjacent cells and what is known as "delay spread". The delay spread is simply the time smearing of a signal. In a home environment, a cell can be a single home. However, since each home essentially employs the same frequency channels, there is a high degree of probability that the communications systems in adjacent homes (e.g., those in neighboring homes) interfere with each other. The interference is compounded when a cell is physically adjacent to another cell as in the case of an apartment complex where interference can stem from any one of the four walls and also from the ceiling or floor.
A possible approach to minimizing the delay spread that was conceived and considered by the inventors of the present invention, but deemed to be an inferior solution as compared with the teachings of the present invention, is the development of sophisticated equalizers to minimize the delay spread. A problem with this approach is that an equalizer must operate at a frequency which is greater than the data communication transmission rate.
The complexity of the hardware and manufacturing constraints of the standard silicon processing techniques are barriers to developing a cost-effective and efficient equalizer. Furthermore, although high speed equalizers are theoretically possible, there is a physical limit to the operation speed of an equalizer imposed by manufacturing considerations that render the development of an equalizer above a certain prespecified operating speed an impossibility.
Accordingly, there remains a need for a high data rate communication system that reduces the interference generated by that communication system and, further, can discriminate between interference generated by another high data rate communication system and the intended data and minimizes the effective delay spread.